what kind of fuel milage are you guys getting with the 350 and the 305 motors. I am thinking about getting me a 3rd gen. i just can't wait. thanks

 

about 15mpg city with a Q-jet

 

I get around 10mpg city driving, although I do have a tiny fuel leak at my fuel pressure regulator. Its like a drip every minute or so. So maybe I get like 11mpg.

 

hey i noticed you live in alabama. where at do you live

 

I get about 17mpg city, and 26 mpg highway.

 

16 commuting, with very little such usage, ~21 highway.

 

I'm not sure what I get around town because my odometer doesn't work but I was able to track my highway mileage on a recent road trip and with a 350 RWHP 383 I was able to get 24MPG with a .62 overdrive and 3.45 gears.

 

Even though my Chevy 305 factory setup has no problems, the mileage is attrocious. Carburators plus Federal emission laws will do that. Only my Mopar 440 New Yorker did worse. This was with a Holley 750 single-pumper/vacuum secondary. What a rocket.
Pontiac/Chevy did market a 4-banger in the early '80's, if you are worried abour fuel prices. Please ignore that last sentence.
Kind of makes me sad that I sold my Triumph. Got 15 in the city/ 38 on the highway, and the 4-banger actually burned rubber.
NO EMISSIONS GADRETRY on that car; and two carbs, to boot.

 

around 10-12 daily commute to school and back.. about 20 miles 5 dollars in gas, gas is 2.19

 

I get about 17-24 with a 350 crate, 3.73's and t-5

 

I've been getting 19 City and 25 Highway. My Camaro is completely stock and original with an LG4 305 and TH700R4.

 

My tune must be waaaayyy off. I get about 12mpg commuting daily from my mostly stock L69.

 

These guys are in The Twilight Zone. Your mileage is way more realistic. Bet your engine is just fine.

 

I guess I should add that I have 3.73s, so I shoudn't expect excellent mileage.

 

The build sheet for my car says '3.23 Positraction', so what is my excuse?

 

To Be honest your gas mileage really depends on how you drive and where you drove. I spent a few days driving around the mountains and yes I did get between 12-15 how ever that is not my typical driving, my typical driving is almost pure highway. How ever even in the city I do not romp on the car ever chance I get, I pull off slowly and drive lightly, Why? cause I like to get the mileage I listed so if thats the twilight zone then Hell I'm staying. Now as for your mileage, there may be absolutly nothing wrong wth your car my freind has a 302 rustang and he only gets about 12. Fuel mileage in my opinion is not a good justifier as to if somethign is wrong with your car. Does it run well, does it feel as strong as it has in the past? Does it start and run easily and smoothly? Does it belch black smoke? And the Most important: Are you happy with what it is right now? thats what tells you if something is wrong with your car. I had a 87 IROC W/a 350 and 3.42's if I got 8 city I was lucky, for what ever reason though the car got decent highway mileage I'd say 17-19. Have no clue why. Maybe my tuning was all messed up maybe it was beat. I have no clue but you know what I was happy with it so it was fine.

 

My Firebird appears to run well.
What really irritates me is the fact that my 440 Mopar with a 750 Holley, and 5,500 pounds to lug down the road, drank less fuel, and was a rocket, to boot.
Computerized timing and low-smog cams must put a big dent in fuel economy.

 

Not too sure on this one but I have a theory, as dumb as it may sound I actually think gearing helps you fuel mileage, provided your driving style does not alter. Here is why I think thats true. On my search/build of the ultimate rear (which never happened for my IROC) I ran 3 different ratios in my car, now provided I accelerated at the same pace with each ratio (which I did using the trusty old butt-o-meter) I found the numericaly lowest ratio gave the overall worst mileage, while the 3.42's over all gave better mileage. now obviously city with the numerically lower gears was the worse and the high way was best mean while the opposite was true with the numerically higher gears. Now this gets interesting when I got into try to build a Oldsmobile that would stomp mustangs. With these lead sleds I had to run alot of gear 3.73 in one and 4.11 in another. Now factory these beasts came with a nice and grandpa-ish 2.41. What I found was the same as the camaro with one diff the highway mileage did not suffer as bad as I anticipated this was ,I think, because the motor sat in it's power range at 65 which meant I needd less gas pedal to keep it there. so in a way I think gear can help mileage. Or I can be totaly wrong and new a new calculator. But anyhow if I am right then that may explain the l69 gas mileage phenomina. we should do a poll of cars with different gears and similar motors that would help see if the theory is right or not.

Sorry for the long winded explainations...

 

You and your butt are probably right about axle ratios. A good fix for low rear ends, and bad fuel economy is a five-speed gearbox, with a good selection of ratios. When the 700-R4 craps out, I want to go for a manual.
I miss the 5-speed in the Triumph. Very low 1st, and a nice selection of ratios in between, ending in overdrive.
Why can't the Pontiac be more British? At the very least, it would handle better.
I think that you see that I miss the old 4-banger.

 

If you've got an LG-4 and you're getting less than 16 mpg, I would make sure there's not a bad component or sensor causing the mcs to run at full rich. You may never notice a difference in performance but you will in mileage. (There's also a possible issue with plugs on the bottom of the q-jet leaking.) I've got a 350 with vortec heads and 3-inch exhaust and I average 20 mpg. When my tps went out the only thing that clued me in was the drop in mileage to around 13-15. There's also an easy fix for the odometer on the forums somewhere. Just my opinion. Hate to see anyone paying for more gas than they need.

 

HAHA Well the 3rd gen did have a 4-banger not the british style where it's a light car and a responsive motor but somewhat the opposite direct where it's a heavy car and a underpowered motor. Yeah I have the T5 right now it's nice to do 65 at 1800-ish with the 3.73's. I really want the t56 same OD just an intermitten step, I hate doing 35-45 too many revs for 4th and lugs 5th. NAF does have a good point though, the carb could be leaking or a Sensore of some sort could be telling theECM to richen it up as much as possible. One thign that made a really large difference on my car was swapping the Carb. I went from the factory HO carb to a carb I had sitting from my oldsmobile. both were CC carbs, only real diff was the olds carb had been rebuilt and flowed for a worked 307 (never built the motor). Basically it seems that carb has a slightly smaller primary side, while the secondary side is noticably larger than the stocker from my camaro. so when everything comes together it maxes out at about 800CFM (it was bench flowed).

 

That would make perfect sense, but my car does run within N.Y.S. smog limits. Gee, 89 octane has gone down to $2.05, here in Brooklyn!. I was in New Jersey last Sunday, and it is even cheaper.

 

I have an 86 Z w/350 vortecs, hot cam, 750 edelbrock (completely untouched other than accel pump adjust), and a tremec 5 speed. with 3.27 gears it got 25-26 hwy mpg and with 3.70 gears it gets 20-21 hwy mpg. Swapping in Dana 44 with 3.54 gears right now-should be somewhere in between for mileage. Not too bad for a 12 second car. Ran 13.34@106 a couple of weeks ago with street tires. Throwing on the drag radials and giving it another try next Wednesday.

 

Is it possible that I am a 'Lead-foot"? If the car passes smog testing, then it must be my driving habits. Either that, or the torque converter is slipping big-time, which I doubt.

 

My car gets the great mileage when I am on the freeway with the cruise set-not rodding around. Short trips take it down to around 17mpg. The 5 speed has alot to do with the mileage-there is NO slippage.